CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Meshing & Mesh Conversion

[snappyHexMesh] first cell height and mesh quality

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   October 1, 2021, 13:33
Default first cell height and mesh quality
  #1
Senior Member
 
Lefteris
Join Date: Oct 2011
Location: UK
Posts: 249
Rep Power: 13
Aeronautics El. K. is on a distinguished road
Hello,

I'm trying to mesh a hull geometry but I can't seem to be able to create prism layers with first cell height 0.001m.

If I increase the first cell height (say to 0.007m) I get some layers.

If I turn off all quality controls in the meshQualityDict I get all the layers (and they look ok) but then the checkMesh fails.

I am using absolute sizes (relativeSizes false) and firstAndRelativeFinal for the thickness model.


I've also attached the checkMesh log file in which I notice the following three lines:

Code:
  <<Number of duplicate (not baffle) faces found: 32. This might indicate a problem.
  <<Number of faces with non-consecutive shared points: 32. This might indicate a problem.
  <<Writing 88 faces with non-standard edge connectivity to set edgeFaces

but I really don't know where to start looking in order to rectify anything that is implied as the underlying issue.


What am I missing?

I would appreciate any help.

Thanks!

PS

Code:
addLayersControls
{
    // Are the thickness parameters below relative to the undistorted
    // size of the refined cell outside layer (true) or absolute sizes (false).
    relativeSizes false;
    
    // thicknessModel keyword that can take the value of:
    // firstAndOverall;
    // firstAndExpansion;
    // finalAndOverall;
    // finalAndExpansion;
    // overallAndExpansion; or
    // firstAndRelativeFinal
    thicknessModel firstAndRelativeFinal;

    firstLayerThickness 0.001;

    // Wanted thickness of final added cell layer. If multiple layers
    // is the thickness of the layer furthest away from the wall.
    // Relative to undistorted size of cell outside layer.
    // See relativeSizes parameter.
    finalLayerThickness 0.5; //$fLayerThickness;

    // Expansion factor for layer mesh
    //~ expansionRatio 1.2;

    //  Overall thickness of the cells (size specification depends on the 
    //  relativeSizes parameter). 
    //  Ignored if using finalLayerThickness or firstLayerThickness.
    //~ thickness 1.5;

    // Minimum thickness of cell layer. If for any reason layer
    // cannot be above minThickness do not add layer.
    // See relativeSizes parameter.
    minThickness 1e-4;


    // Per final patch (so not geometry!) the layer information
    layers
    {
        bowPort
        {
            nSurfaceLayers 15;   
            //~ thicknessModel firstAndRelativeFinal;
            //~ firstLayerThickness 0.001;
            //~ finalLayerThickness 0.5;
            //~ thickness 0.2;
            //~ expansionRatio 1.2;
            //~ minThickness 0.0;
        }
...
...
...
OF version is 2012
Attached Files
File Type: txt checkmesh.txt (6.9 KB, 1 views)
__________________
Lefteris


Last edited by Aeronautics El. K.; October 1, 2021 at 15:46.
Aeronautics El. K. is offline   Reply With Quote

Old   October 10, 2021, 16:23
Default
  #2
Senior Member
 
Lefteris
Join Date: Oct 2011
Location: UK
Posts: 249
Rep Power: 13
Aeronautics El. K. is on a distinguished road
ok, seeing that no one apparently has any clues to tackle the original question, I'll ask something (hopefully) easier.



Does anyone know which parameter in the meshQualityDict controls the maximum allowed aspect ratio of the cells?
__________________
Lefteris

Aeronautics El. K. is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
y+ = 1 boundary layer mesh with snappyHexMesh Arzed23 OpenFOAM Running, Solving & CFD 1 July 10, 2019 09:56
[snappyHexMesh] SnappyHexMesh no layers and no decent mesh for complex geometry pizzaspinate OpenFOAM Meshing & Mesh Conversion 1 February 25, 2015 08:05
[ICEM] Negative volume error in hybrid mesh siw ANSYS Meshing & Geometry 4 September 3, 2014 06:25
first cell height of a mesh Tensian Main CFD Forum 0 February 20, 2014 13:48
fluent add additional zones for the mesh file SSL FLUENT 2 January 26, 2008 12:55


All times are GMT -4. The time now is 04:52.